Fix a bug in group_app
Fix a bug in group_app

If context is not set, kwargs['context'] will raise an exception.

Patch by: Sverre Rabbelier

--HG--
extra : convert_revision : svn%3A32761e7d-7263-4528-b7be-7235b26367ec/trunk%401938

SRabbelier/Melange,SRabbelier/Melange,SRabbelier/Melange,SRabbelier/Melange,SRabbelier/Melange,SRabbelier/Melange,SRabbelier/Melange,SRabbelier/Melange,SRabbelier/Melange